Air bag device

ABSTRACT

There are provided an inflator  31 ; a cylindrical holder  32  where the inflator  31  is accommodated inside; and a bag-shaped airbag  35  accommodating the holder at its opening portion  34  and folded in an ordinary situation to be expandable by a gas G discharged from the inflator  31 , wherein a protecting cloth  50  distinct from the airbag  35  is arranged on an inner face of the opening portion  34  of the airbag  35.

TECHNICAL FIELD

[0001] The present invention relates to an-airbag apparatus whichinstantaneously expands to protect a passenger of his/her own automobileat a time of a collision of an automobile, particularly so-called alateral collision where another automobile collides against a sideportion of his/her own automobile.

BACKGROUND ART

[0002] As an airbag apparatus for protecting a passenger, there is, forexample, one disclosed in U.S. Pat. No. 5,586,782 or one disclosed inJapanese Patent Application Laid-Open No. 8-207689.

[0003] The former, namely an airbag apparatus for lateral collision(DUAL PRESSURE SIDE IMPACT AIRBAG) disclosed in U.S. Pat. No. 5,586,782,is configured such that, at a time of a lateral collision of anautomobile, an electrical signal is transmitted to an inflator via aharness for ignition when the collision is detected, gas generated fromthe inflator ignited is introduced from a gas discharging hole into anairbag folded to be accommodated within a case body in a backrest in anordinary situation of the automobile to expand the same, the expandedairbag presses and opens a lid of the case body, and the airbag isspread between a passenger and a passenger compartment side wall, sothat an impact generated when the passenger secondarily collides againstthe passenger compartment side wall is absorbed by the airbag.

[0004] The airbag is structured such that a bag body formed in agenerally L-shaped configuration with a head protecting portion and achest protecting portion is divided into a gas passage to the headprotecting portion and a gas passage to the chest protecting portion bya dividing plate or a sewn portion, and the gas discharged from theinflator is filled into the respective protecting portions in a shorttime.

[0005] Also, the latter, namely an airbag for lateral collisiondisclosed in Japanese Patent Application Laid-Open No. 08-207689, isstructured such that an airbag is folded and accommodated within abackrest in an ordinary situation of an automobile, like the former, andat a time of a lateral collision of an automobile the airbag is abruptlyexpanded by discharged gas rapidly from an inflator into the airbag viaa supporting pipe so that an impact generated when a passengersecondarily collides against a passenger compartment side wall isabsorbed by the airbag.

[0006] However, in a structure of such a conventional airbag apparatus,as the inflator (the former) or the supporting pipe (the latter) ishoused in the airbag of the airbag apparatus from an opening portionthereof, there is a risk that an inner face of the airbag may be injuredby friction between the airbag and an edge portion of the inflator or aholder for holding the inflator inside the airbag.

[0007] Also, the gas discharged from the inflator tends to concentrateon the vicinity of an inflator-mounting portion positioned at theopening portion of the airbag, which is required to be improved.

[0008] The present invention has been achieved in view of the problemsin such a conventional art, and an object thereof is to provide anairbag apparatus which prevents the friction between the airbag and theedge portion of the inflator or the holder for holding the inflatorinside the airbag and the injury of the airbag due to a high temperaturegas discharged from the inflator.

DISCLOSURE OF INVENTION

[0009] In order to achieve the above object, the invention of a firstaspect comprises: an inflator; and an airbag accommodating the inflatorat its opening portion and folded in an ordinary situation to beexpandable by a gas discharged from the inflator, wherein a protectingcloth distinct from the airbag is arranged on an inner face of theopening portion of the airbag.

[0010] According to the invention of the first aspect, the airbag can beprevented by means of the protecting cloth from being injured byfriction between the airbag and an edge portion of the inflator and ahigh temperature gas discharged from the inflator.

[0011] The invention of a second aspect comprises: an inflator; acylindrical holder inside which the inflator is accommodated; and anairbag accommodating the inflator at its opening portion and folded inan ordinary situation to be expandable by the gas discharged from theinflator, wherein a protecting cloth distinct from the airbag isarranged on an inner face of the opening portion of the airbag.

[0012] According to the invention of the second aspect, the airbag canbe prevented by means of the protecting cloth from being injured byfriction between the airbag and an edge portion of the holder forholding the inflator inside and a high temperature gas discharged fromthe inflator.

[0013] As a preferred aspect, a portion of the protecting clothpositioned at a side which is supported by an inside part of it anautomobile is thicker than a portion of the protecting cloth positionedat a side which is not supported by the inside part.

[0014] According to this aspect, even when friction occurs between theairbag and an edge portion of the inflator or the holder, there is amargin where the friction can freely be avoided in the portion of theprotecting cloth positioned at the side which is not supported by theinside part, whereby the airbag itself can securely be protected bymaking thick the portion of the airbag positioned at the side wherethere is not the margin. Also, the portion of the protecting clothpositioned at the side which is supported by the inside part which isapt to be influenced by the high temperature gas discharged from theinflator is made thick, so that the airbag itself can securely beprotected.

[0015] Also, as a preferred aspect, a heat resistant temperature at aportion of the protecting cloth positioned at a side which is supportedby an inside part of an automobile is higher than that at a portion ofthe protecting cloth positioned at a side which is not supported by theinside part.

[0016] According to this aspect, even when friction occurs between theairbag and the edge portion of the inflator or the holder, as theportion of the protecting cloth positioned at the side which is notsupported by the inside part is apt to be air-cooled, the heat resistanttemperature of the portion of the protecting cloth positioned at theside which is supported by the inside part is made high, so that theairbag itself can securely be protected.

[0017] As a further preferred aspect, the opening portion of the airbagis formed so as to be overlapped at its supporting portion forsupporting the inflator or the holder accommodating the inflator insidethereof, and a reinforcing cloth which is to resist against the heat ofthe gas discharged from the inflator is held on the overlapped portion.

[0018] According to this aspect, as the airbag is prevented from beinginjured by direct discharge of the inflator without increasing thenumber of component parts, the number of airbag forming steps such assewing can remarkably be reduced.

BRIEF DESCRIPTION OF DRAWINGS

[0019]FIG. 1 is a whole perspective view of a seat mounted with anairbag apparatus according to an embodiment of the present invention;

[0020]FIG. 2 is a sectional view taken along line II-II in FIG. 1;

[0021]FIG. 3 is a sectional view showing a state where an airbag hasbeen expanded from a state shown in FIG. 2;

[0022]FIG. 4 is an exploded side view of only the airbag of FIG. 2 at anexpanded time, a holder, and the like;

[0023]FIG. 5 is a sectional view taken along line V-V in FIG. 4; and

[0024]FIG. 6 is a sectional view taken along line VI-VI after a boltmember 38 is inserted into through holes 56 a and 57 a of a firstreinforcing cloth 56 and a second reinforcing cloth 57.

BEST MODE FOR CARRYING OUT THE INVENTION

[0025] FIGS. 1 to 6 show an embodiment. As shown in FIGS. 1 and 2, aseat 1 comprises a backrest 2 and a seat cushion 3, and the backrest 2is arranged at a position opposing to a passenger compartment inner sidewall 4 such as a door trim, a center pillar inner panel 5 or the like. Areference character 6 denotes a head rest, a reference character 7denotes a lap belt, and a reference character 8 denotes a shoulder belt.

[0026] As shown in FIG. 2, the backrest 2 comprises a backrest frame 10;a cushion pad 11 arranged at a front side FR of the backrest frame 10; aside cushion 12 arranged on a side SD of the backrest frame 10; a firstshock absorbing member 13 of a slab urethane type arranged at the frontside FR of a central portion CT of the cushion pad 11; a first outerskin 14 covering the first shock absorbing member 13; a second shockabsorbing member 15 of a slab urethane type arranged at the front sideFR on the side SD of the cushion pad 11; a second outer skin 16 coveringthe second shock absorbing member 15; a third shock absorbing member 17of a slab urethane type arranged on the side SD of the side cushion 12;a third outer skin 18 covering the third shock absorbing member 17; anairbag apparatus 19 arranged between a side portion of the cushion pad11 and an inner face of the side cushion 12 by means described later; asewn portion 20 holding the first shock absorbing member 13, the firstouter skin 14, the second shock absorbing member 15, and the secondouter skin 16; an opening and rupturing portion 21 configured by sewingthe second shock absorbing member 15, the second outer skin 16, thethird shock absorbing member 17, and the third outer skin 18 so as to beruptured by a predetermined pressure; a cloth-like protecting member 23for protecting the side cushion 12, one side of which is sewn to theopening and rupturing portion 21, the other side thereof being held by awire of the backrest frame 10; and a sewn portion 24 holding the sidecushion 12, the third shock absorbing member 17 and the third outer skin18.

[0027] As shown in FIG. 4, the airbag apparatus 19 comprises avertically elongated cylindrical holder 32 where an inflator 31 isaccommodated, the inflator being capable of being ignited bytransmission of a collision electric signal from an unillustrated sensorthrough an ignition harness 30; an airbag 35 arranged such that itsopening portion 34 faces a discharging hole 33 of the holder 32 andfolded in an ordinary situation of an automobile to be expandable by agas G discharged from the inflator 31; and a case body 37 (refer to FIG.2) made of synthetic resin, the case body 37 covering the holder 32 andthe airbag 35 and having an opening portion 36 rupturable by expansionof the airbag 35.

[0028] As shown in FIGS. 4 and 6, bolt members 38 are provided in aprojecting manner on the holder 32. The bolt members 38 are exposedoutside via unillustrated through holes of the case body 37 and they areinserted into unillustrated through holes to be screwed to nuts 40. Atthis time, the discharging hole 33 of the holder 32 faces on the frontside FR and it is arranged at a lower side DW.

[0029] As shown in FIG. 1, the airbag 35 is formed in a bag shape so asto be expandable in a generally L configuration with a head protectingportion 41 and a chest protecting portion 42 by the gas G dischargedfrom the inflator 31, and it is folded in an ordinary situation of anautomobile.

[0030] A protecting cloth 50 distinct from the airbag 35 is arranged onan inner face of the opening portion 34 of the airbag 35.

[0031] The protecting cloth 50 comprises a first protecting cloth 51attached to an inner face of the airbag 35 positioned at a side (a sideopposed to or facing a side which is supported by an inside part) whichis not supported by the backrest frame 10 or the like and a secondprotecting cloth 52 and a third protecting cloth 53 attached in layersto an inner face of the airbag 35 positioned at a side which issupported by the inside part. The plate thickness of the second andthird protecting clothes 52 and 53 is thicker than that of the firstprotecting cloth 51. The second and third protecting clothes 52 and 53are not put in layers but they may be configured in one piece.

[0032] In the protecting cloth 50, the heat resistant temperatures ofthe second and third protecting clothes 52 and 53 are preferably higherthan that of the first protecting cloth 51.

[0033] The first protecting cloth 51 and the third protecting cloth 53are respectively formed in the almost same size as those of the left andthe right clothes 35 a and 35 b configuring the airbag 35. The secondprotecting cloth 52 is arranged at a position nearest to the inflator31, and it is formed in a size approximating to the discharging hole 33,namely half a vertical size of each of the first protecting cloth 51 andthe third protecting cloth 53.

[0034] The opening portion 34 of the airbag 35 is folded at a supportingportion 55 for supporting the inflator 31 or the holder 32 accommodatingthe inflator 31 therein so as to be overlapped, and a first reinforcingcloth 56 and a second reinforcing cloth 57 capable of resisting againstthe heat of the gas discharged from the inflator 31 are held on thesupporting portion 55 thus overlapped. A reference characters 56 a and57 a are through holes formed on the first reinforcing cloth 56 and thesecond reinforcing cloth 57 so as to be insertable with the bolt members38, respectively. As shown with a cross-sectional view of the airbagapparatus in FIG. 6, the first reinforcing cloth 56 is positioned nearerto the holder 32 than the second reinforcing cloth 57. Accordingly, evenwhen the airbag 35 is injured by a corner of the discharging hole 33side of the inflator 31, the airbag 35 is prevented from being worn outby extending the first reinforcing cloth 56 sufficiently towards thedischarging hole 33 side of the inflator 31, and the airbag 35 itself issecurely protected so that the airbag can securely be spread.

[0035] As the embodiment of the invention is structured in the abovemanner, when the inflator 31 is ignited by any signal so that the gas Gis discharged from the discharging hole 33 of the holder 32 as shownwith a white arrow in FIG. 3, the airbag 35 which has been folded in anordinary situation, particularly the chest protecting portion 42, israpidly expanded towards the front side FR of the automobile by the gasG discharged from the inflator 31, and the opening portion 36 of thecase body 37 covering the airbag 35 is put in a ruptured state, so thatthe case body 37 is opened in a linear shape and the airbag 35 isfurther expanded.

[0036] That is, as the chest protecting portion 42 of the airbag 35which has been folded in the ordinary situation is first expanded andthen the gas can be introduced into the head protecting portion 41 side,the chest protecting portion 42 enters securely in between the chest ofa passenger, and the door trim 4 and the center pillar inner panel 5, sothat a secondary collision energy of the passenger against the door trim4 and the center pillar inner panel 5 can sufficiently be absorbed.

[0037] Injury of the airbag 35 due to friction between the airbag 35 andthe edge portion of the holder 32 holding the inflator inside and thehigh temperature gas G discharged from the inflator 31 can be preventedby the protecting cloth 50.

[0038] Even when friction occurs between the airbag and the edge portionof the inflator 31 or the holder 32, as the cloth 35 b of the airbag 35positioned at the side which is not supported by the inside part has amargin where it can avoid the friction freely, the cloth 35 a of theairbag 35 positioned at the side in which there is not the margin ismade thicker by the third protecting cloth 53, thereby allowing a secureprotection of the airbag 35 itself.

[0039] Also, the cloth 35 a of the airbag 35 positioned at the sidewhich is supported by the inside part which is apt to be influenced bythe high temperature gas G discharged from the inflator 31 is madethicker, thereby allowing a secure protection of the airbag 35 itself.

[0040] Even when friction occurs between the airbag and the edge portionof the inflator 31 or the holder 32, as the cloth 35 b of the airbag 35positioned at the side which is not supported by the inside part is aptto be air-cooled. Accordingly, the heat resistant temperature of thecloth 35 a of the airbag 35 positioned at the side which is supported bythe inside part is made higher, thereby allowing a secure protection ofthe airbag 35 itself.

[0041] As the injury of the airbag 35 due to direct discharge of the gasG from the inflator 31 can be prevented without increasing the number ofcomponent parts, the number of steps for forming the airbag 35 such assewing can remarkably be reduced.

[0042] The above explanation is directed to an explanation of the casewhere the holder 32 is used, but the invention may be structured suchthat the inflator 31 is arranged directly at the opening portion 34 ofthe airbag 35. Even in such a case, the injury of the airbag 35 due tothe friction between the airbag and the edge portion of the inflator 31and the high temperature gas G discharged from the inflator 31 can beprevented by the protecting cloth 50.

INDUSTRIAL APPLICABILITY

[0043] As mentioned above, the airbag apparatus according to the presentinvention is useful as an apparatus for protecting a passenger at a timeof collision of an automobile.

1. An airbag apparatus comprising: an inflator to discharge a gas; anairbag having an opening portion for the inflator accommodated inside,the airbag being folded in an ordinary situation, the airbag to beexpandable by the gas to be discharged from the inflator; and aprotecting cloth distinct from the airbag, the protecting cloth beingarranged on an inner face of the opening portion of the airbag.
 2. Anairbag apparatus comprising: an inflator to discharge a gas; acylindrical holder for the inflator accommodated inside; an airbaghaving an opening portion for the holder accommodated therein, theairbag folded in an ordinary situation, the airbag to be expandable bythe gas to be discharged from the inflator; and a protecting clothdistinct from the airbag, the protecting cloth being arranged on aninner face of the opening portion of the airbag.
 3. An airbag apparatusaccording to claim 1 , wherein a portion of the protecting clothpositioned at an side which is supported by an inside part of anautomobile is thicker than a portion of the protecting cloth positionedat a side which is not supported by the inside part.
 4. An airbagapparatus according to claim 1 , wherein a heat resistant temperature ata portion of the protecting cloth positioned at a side which issupported by an inside part of an automobile is higher than that at aportion of the protecting cloth positioned at a side which is notsupported by the inside part.
 5. An airbag apparatus according to claim1 wherein, the opening portion of the airbag is folded so as to beoverlapped at its supporting portion for supporting the inflator or theholder accommodating the inflator inside thereof, and a reinforcingcloth which is to resist against the heat of the gas discharged from theinflator is held on the overlapped portion.